Brief note about 3D printing, how it works.
Picture a robot-controlled hot glue gun that uses plastic instead of glue, and you have the basics of a 3D printer. Strands of plastic are fed into a print head, which is heated up to melt the material. The print head moves around very precisely in three dimensions and drops lines of plastic onto the print bed—the table on which it prints. The printer does this over and over, building up layers of plastic until it forms a 3D part….